This application claims priority from Canadian Patent Application No. 2,270,643 filed Apr. 29, 1999 titled PLASTIC LUMBER SPACING OR PILING STRIP.
The present invention relates to a portable device, and in particular a plastic strip, for supporting and spacing wood products during a kiln or other drying process. Although used for a variety of purposes, such devices are commonly known as lumber spacing or piling strips.
One common type of lumber spacing or piling strip is an all wood strip. An all wood strip has the disadvantage of becoming brittle and susceptible to breakage after only a few uses due to the temperatures and pressures of the kiln drying process, which may reach 230 degrees Fahrenheit at 60 pounds per square inch pressure. Strips made from wood are also susceptible to breakage during handling and reuse. Thus conventionally all wood strips have to be replaced on a continuous basis increasing the cost of wood product production.
Wood strips also have drawbacks caused by the moisture content of the wood product being dried. The moisture content may cause the wood strips to warp, check and split during the kiln drying process daring moisture loss. Perhaps more importantly, wood strips suffer from a disadvantage that they do not allow for air venting between the strips and the wood product during the drying process and so may produce wet spots in the lumber which otherwise has been dried. Further, due to the smooth planar surfaces of wood strips, the lumber products sometimes creep relative to the strips and may become warped.
It is thus desirable in the industry to have, and an object of the present invention to provide, a durable, continually re-usable, vented plastic lumber spacing or piling strip that is able to withstand the temperatures, pressures and moisture, for example, of the kiln drying process.
In summary the spacing or piling strip used for spacing or piling lumber of the present invention includes a plastic substantially parallelepiped member having opposite first and second weight-bearing surfaces thereon. The first and second surfaces are contoured to provide air venting means. Thus when the strip has at least one wood product stacked on it so as to bear against the first or second weight-bearing surface, a contact surface of the wood product in contact with the strip is dried during a drying process applied to the wood product.
In embodiments not intended to be limiting, the air venting means is:
(a) at least one channel on the first and second surfaces, wherein the channel extends from opposite edges of the strip;
(b) a plurality of channels on the first and second surfaces, wherein the plurality of channels extend from opposite edges of the strip;
(c) at least one longitudinally extending channel on the first and second surfaces, wherein the longitudinally extending channel extends from opposite edges of the strip;
(d) a plurality of longitudinally extending channels on the first and second surfaces, wherein the plurality of longitudinally extending channels extend from opposite edges of the strip;
(e) at least one groove on the first and second surfaces, wherein the groove extends from opposite edges of the strip;
(f) a plurality of grooves on the first and second surfaces, wherein the plurality of grooves extend from opposite edges of the strip;
(g) at least one longitudinally extending groove on the first and second surfaces, wherein the longitudinally extending groove extends from opposite edges of the strip;
(h) a plurality of longitudinally extending grooves on the first and second surfaces, wherein the plurality of longitudinally extending grooves extend from opposite edges of the strip;
(i) is at least one corrugation on the first and second surfaces, wherein the corrugation extends from opposite edges of the strip;
(j) a plurality of corrugations on the first and second surfaces, wherein the plurality of corrugations extend from opposite edges of the strip;
(k) at least one longitudinally extending corrugation on the first and second surfaces, wherein the longitudinally extending corrugation extends from opposite edges of the strip;
(l) a plurality of longitudinally extending corrugations on the first and second surfaces, wherein the plurality of longitudinally extend corrugations extending from opposite edges of the strip;
(m) a gridwork of bumps on the first and second surfaces, wherein the grid work extends from opposite edges of the strip; or,
(n) a gridwork of striations on the first and second surfaces, wherein the grid work extends from opposite edges of the strip.
In one embodiment the strip is a rectangular parallelepiped. It may advantageously be elongate and thin (relative to the dimensions of its weight-bearing surfaces) between the first and second surfaces.